Ultrasound catheter and ultrasound catheter system

This application is a continuation of International Application No. PCT/JP2021/008616 filed on Mar. 5, 2021, which claims priority to Japanese Application No. 2020-043662 filed on Mar. 13, 2020, the entire content of both of which is incorporated herein by reference.

The present disclosure generally relates to an ultrasound catheter and an ultrasound catheter system that acquire an image by being inserted into an inner lumen such as a heart or a blood vessel.

When a lesion is examined from a heart, a blood vessel, or the like, an ultrasound catheter that is inserted into an inner lumen of a living body and acquires an image by using ultrasound is used (for example, see Japanese Patent No. 6,073,295). The ultrasound catheter includes a transducer for transmitting and receiving ultrasound, a drive shaft that rotates the transducer, and a sheath that rotatably accommodates the transducer and the drive shaft. The transducer is rotationally driven by the drive shaft in the sheath to transmit and receive the ultrasound, and acquires an image in the living body.

An inner lumen of a blood vessel of a heart, a lower limb, or an abdomen is larger than that of a blood vessel such as a coronary artery. In observation with an ultrasound catheter in the large inner lumen, as a distance from the ultrasound transducer to an observation target increases, the ultrasound spreads, and therefore observation of the observation target becomes relatively difficult. Therefore, an ultrasound catheter that can acquire a relatively highly accurate image even in a heart, a blood vessel of a lower limb or an abdomen, or the like having a large inner lumen is desired.

An ultrasound catheter and an ultrasound catheter system are disclosed that can acquire an image of an observation target with relatively high accuracy even when the ultrasound catheter and the ultrasound catheter system are inserted into a relatively large inner lumen.

An ultrasound catheter is disclosed that includes: an outer sheath in which an accommodation lumen configured to extend from a proximal end to a distal end is formed; an inner sheath configured to move in the accommodation lumen along an axis of the outer sheath; a drive shaft configured to rotate in the inner sheath and/or the outer sheath; and a transducer that is disposed on a distal side of the inner sheath in the accommodation lumen, and that is fixed to a distal end of the drive shaft, in which the outer sheath includes a bent portion that is bent and shaped in advance at a predetermined angle on a proximal side of a most distal end of the accommodation lumen, and a tubular portion that has an axis having a radius of curvature larger than a radius of curvature of an axis of the bent portion, the tubular portion being positioned on a distal side of the bent portion and on the proximal side of the most distal end of the accommodation lumen, and the outer sheath is rotatable with respect to the inner sheath.

An ultrasound catheter system is disclosed that includes an ultrasound catheter; and a drive device configured to drive the ultrasound catheter, in which the ultrasound catheter includes an outer sheath in which an accommodation lumen configured to extend from a proximal end to a distal end is formed, an inner sheath configured to move in the accommodation lumen along an axis of the outer sheath, a drive shaft configured to rotate in the inner sheath and/or the outer sheath, a transducer that is disposed on a distal side of the inner sheath in the accommodation lumen, and that is fixed to a distal end of the drive shaft, a first housing to which a proximal portion of the outer sheath is fixed and through which the drive shaft and the inner sheath pass, and a second housing that is disposed on a proximal side of the first housing, to which a proximal portion of the inner sheath is fixed, and configured to rotatably hold the drive shaft, in which the outer sheath includes a bent portion that is bent and shaped in advance at a predetermined angle on a proximal side of a most distal end of the accommodation lumen, and a tubular portion that has an axis having a radius of curvature larger than a radius of curvature of an axis of the bent portion, the tubular portion being positioned on a distal side of the bent portion and on the proximal side of the most distal end of the accommodation lumen, in which the outer sheath is rotatable of the inner sheath, in which the drive device includes a proximal side support portion configured to support the second housing, a movement portion configured to move the proximal side support portion in an axial direction, a drive unit configured to transmit a rotational force to the drive shaft, and a distal side support portion configured to rotatably support the first housing.

Since the outer sheath is rotated with respect to the inner sheath, the ultrasound catheter configured as described above can freely adjust a distance and an angle of the transducer, which is in the accommodation lumen positioned in the tubular portion on the distal side of the bent portion, with respect to an observation target. Therefore, the ultrasound catheter can acquire an image of the observation target with relatively high accuracy even when the ultrasound catheter is inserted into a relatively large inner lumen.

Since the first housing supported by a distal side support portion is rotatable, by rotating the outer sheath fixed to the first housing with respect to the inner sheath, the ultrasound catheter system configured as described above can freely adjust the distance and the angle of the transducer, which is in the accommodation lumen positioned in the tubular portion on the distal side of the bent portion, with respect to the observation target. Therefore, the ultrasound catheter system can acquire an image of the observation target with relatively high accuracy even when the ultrasound catheter system is inserted into a relatively large inner lumen.

An axis of the tubular portion may be linear. Accordingly, since the transducer to be moved in the accommodation lumen is moved linearly, obtained images can be rather easily connected in the axial direction, and a relatively highly accurate three-dimensional image can be acquired.

The outer sheath may include may include two or more bent portions at different positions in an axial direction. Accordingly, as compared with a case where the outer sheath includes only one bent portion, it is rather easy to dispose the transducer at a desirable position.

At least one of the two or more bent portions may be bent toward a side opposite to another of the two or more bent portions. Accordingly, the distal portion of the outer sheath can be disposed at a position offset from the proximal portion of the outer sheath while having a shape close to parallel to the proximal portion of the outer sheath. Therefore, the distal portion of the outer sheath is rather easily disposed along a wall of an inner lumen of a heart or an inner lumen such as a blood vessel. Therefore, the transducer that pulls back along the axis can be disposed at a desirable position with respect to the observation target in a relatively large range of the outer sheath in the axial direction.

The ultrasound catheter may include the two or more portions bent toward the same side. Accordingly, an angle of each bent portion of the outer sheath can be reduced. Therefore, it is possible to reduce a load on the drive shaft that is movable in an axial direction while being rotated in the bent portion, and to help prevent occurrence of a rotation failure or a failure in movement in the axial direction. Further, since the outer sheath can be largely bent as a whole by the two or more bent portions, orientation is facilitated.

The transducer may be configured to move in the accommodation lumen in an axial direction beyond the bent portion. Accordingly, the transducer can acquire an image of an internal structure of a living body positioned in a relatively large range beyond the bent portion in an axial direction of the accommodation lumen.

A bending angle of the axis of the bent portion may be 5° to 20°. When the bending angle is not too small, it is relatively easy to set an offset amount of the outer sheath to a desirable value. Further, when the bending angle is not too large, rotation and movement in the axial direction of the drive shaft, which moves in the axial direction while being rotated in a state of being bent in the bent portion, are less likely to be hindered.

The outer sheath may include a proximal side tubular portion on a proximal side of a bent portion on a most proximal side, and a distal portion length, which is a length from the bent portion on a most proximal side to a most distal end of the outer sheath along a linear reference line where an axis of at least a distal portion of the proximal side tubular portion is positioned, may be, for example, 20 mm to 150 mm. Accordingly, a length of a portion offset with respect to the proximal side tubular portion can be set, for example, to a length appropriate for observation in a heart or a blood vessel having a relatively large inner lumen.

The outer sheath may include the proximal side tubular portion on the proximal side of the bent portion on the most proximal side, and an offset amount, which is a length from the linear reference line where the axis of at least the distal portion of the proximal side tubular portion is positioned to an axis of a portion farthest in a direction perpendicular to the reference line of a portion on a distal side of the bent portion of the outer sheath on the most proximal side, may be, for example, 5 mm to 30 mm. Since the offset amount has an appropriate magnitude, it is relatively easy to bring the outer sheath close to the observation target in the heart or the blood vessel having the large inner lumen.

An ultrasound catheter is disclosed, comprising: an outer sheath, the outer sheath includes an accommodation lumen configured to extend from a proximal end to a distal end of the outer sheath; a drive shaft configured to move in an axial direction of the outer sheath; a transducer fixed to a distal end of the drive shaft; the outer sheath includes a bent portion, the bent portion being bent and shaped in advance at a predetermined angle on a proximal side of a most distal end of the accommodation lumen, and a tubular portion having a linear axis, the tubular portion being positioned on a distal side of the bent portion and on the proximal side of the most distal end of the accommodation lumen; the outer sheath is rotatable with respect to the drive shaft; and wherein the transducer is configured to move in the accommodation lumen in the axial direction of the outer sheath beyond the bent portion.

Set forth below with reference to the accompanying drawings is a detailed description of embodiments of an ultrasound catheter and an ultrasound catheter system that acquire an image by being inserted into an inner lumen such as a heart or a blood vessel. Note that since embodiments described below are preferred specific examples of the present disclosure, although various technically preferable limitations are given, the scope of the present disclosure is not limited to the embodiments unless otherwise specified in the following descriptions. Dimensional ratios in the drawings may be exaggerated and different from actual ratios for convenience of description. Further, in the present specification, a side to be inserted into a living body is referred to as a “distal side”, and a side to be operated is referred to as a “proximal side”.

10 An ultrasound catheteraccording to the present embodiment is a device that can acquire a three-dimensional image of a heart or a blood vessel by being mainly inserted into the heart or the blood vessel.

1 2 FIGS.and 10 20 30 40 50 10 60 70 As shown in, the ultrasound cathetercan include an outer sheath, an inner sheath, a transducer unit, and a drive shaft. The ultrasound catheterfurther can include a first housingand a second housing.

20 20 21 22 The outer sheathis a tubular body to be inserted into an inner lumen of a living body. The outer sheathincludes an outer sheath bodyand a distal end cap.

21 23 24 25 26 27 28 21 23 24 25 26 27 The outer sheath bodycan include, from a proximal end toward a distal end, a proximal side tubular portion, a first bent portion(bent portion), a first tubular portion(tubular portion), a second bent portion(bent portion), and a second tubular portion(tubular portion). An accommodation lumenthat extends from the proximal end to the distal end of the outer sheath bodyis formed inside the proximal side tubular portion, the first bent portion, the first tubular portion, the second bent portion, and the second tubular portion.

23 23 60 24 23 25 24 26 25 27 26 27 22 The proximal side tubular portionis a tubular body having a substantially straight line-shaped axis. A proximal portion of the proximal side tubular portionis fixed to the first housing. The first bent portionis a tubular body positioned on a distal side of the proximal side tubular portionand having a bent axis. The first tubular portionis a tubular body positioned on a distal side of the first bent portionand having a straight line-shaped axis. The second bent portionis a tubular body positioned on a distal side of the first tubular portionand having a bent axis. The second tubular portionis a tubular body positioned on a distal side of the second bent portionand having a straight line-shaped axis. A distal portion of the second tubular portionis fixed to the distal end cap.

23 25 24 26 23 24 26 23 The axis of the proximal side tubular portionmay not be straight line-shaped, but may be curved to some extent. In this case, a radius of curvature of the axis of the first tubular portionis larger than a radius of curvature of the axis of the first bent portionand a radius of curvature of the second bent portion. That is, the proximal side tubular portionhas a shape closer to a straight line than the first bent portionand the second bent portion. The straight line can be defined as having an infinite radius of curvature. The axis of at least a distal portion of the proximal side tubular portionis positioned on a linear reference line X.

25 25 24 26 25 24 26 The axis of the first tubular portionmay not be straight line-shaped, but may be curved to some extent. In this case, a radius of curvature of the axis of the first tubular portionis larger than the radius of curvature of the axis of the first bent portionand the radius of curvature of the second bent portion. That is, the first tubular portionhas a shape closer to a straight line than the first bent portionand the second bent portion.

27 27 24 26 27 24 26 27 23 23 The axis of the second tubular portionmay not be straight line-shaped, but may be curved to some extent. In this case, a radius of curvature of the axis of the second tubular portionis larger than the radius of curvature of the axis of the first bent portionand the radius of curvature of the second bent portion. That is, the second tubular portionhas a shape closer to a straight line than the first bent portionand the second bent portion. The axis of the second tubular portionis substantially parallel to the axis of the proximal side tubular portion, but may not be parallel to the axis of the proximal side tubular portion.

24 26 2 20 20 2 24 20 24 26 50 24 26 24 26 2 20 50 A bending angle θ of the first bent portionand the second bent portionis not particularly limited, but is preferably, for example, 5° to 20°. When the bending angle θ is too small, an offset amount Lof a distal portion of the outer sheathwith respect to a proximal portion of the outer sheathbecomes relatively small. The offset amount Lis a length from the reference line X to an axis of a portion farthest from the reference line X in a direction perpendicular to the reference line X among portions on the distal side of the first bent portionof the outer sheath. When the bending angle θ of the first bent portionor the second bent portionis too large, rotation and movement in an axial direction of the drive shaft, which moves in the axial direction while rotating in a state of being bent inside the first bent portionand the second bent portion, are likely to be hindered. On the contrary, when the bending angle θ of the first bent portionand the second bent portionhas an appropriate size, it is relatively easy to set the offset amount Lof the outer sheathto a desirable value while stably maintaining the rotation and the movement in the axial direction of the drive shaft.

1 24 20 24 20 1 2 20 20 1 2 20 20 1 2 20 A distal portion length L, which is a length along the reference line X from the first bent portionto a most distal end of the outer sheath, is not particularly limited, but is preferably, for example, 20 mm to 150 mm. Therefore, a length along the reference line X of an offset portion (a portion where the axis deviates from the reference line X in a direction perpendicular to the reference line X) on the distal side of the first bent portionof the outer sheathcan be appropriately set for use in the heart or the blood vessel having a large inner lumen. Further, when the distal portion length Lis too short, the offset amount Lof the distal portion of the outer sheathwith respect to the proximal portion of the outer sheathis likely to be relatively small. When the distal portion length Lis too long, the offset amount Lof the distal portion of the outer sheathwith respect to the proximal portion of the outer sheathis likely to be relatively large. On the contrary, when the distal portion length Lis an appropriate length, it is relatively easy to set the offset amount Lof the outer sheathto a desirable value.

2 2 20 The offset amount Lis not particularly limited, but is preferably, for example, 5 mm to 30 mm. When the offset amount Lhas an appropriate magnitude, it is relatively easy to bring the outer sheathclose to an observation target portion in the heart or the blood vessel having the large inner lumen.

21 40 30 50 28 40 30 50 21 28 21 40 50 21 21 21 22 23 21 60 27 21 22 21 The outer sheath bodyaccommodates the transducer unit, the inner sheath, and the drive shaftin the accommodation lumen. The transducer unit, the inner sheath, and the drive shaftin the outer sheath bodycan move in the accommodation lumenalong the axis of the outer sheath body. Further, the transducer unitand the drive shaftin the outer sheath bodycan rotate in the outer sheath body. The outer sheath bodyis a cylindrical body that is open only at a proximal end and closed at a distal end by the distal end cap. The proximal portion of the proximal side tubular portionthat forms a proximal portion of the outer sheath bodyis fixed to the first housing. The distal portion of the second tubular portionthat forms a distal portion of the outer sheath bodyis fixed to the distal end cap. The proximal portion of the outer sheath bodymay be provided with a reinforcing body such as a braided wire.

In the present embodiment, two bent portions are provided, but one bent portion may be provided, or three or more bent portions may be provided. Further, in the present embodiment, two tubular portions are provided, but one tubular portion may be provided, or three or more tubular portions may be provided.

22 21 22 21 10 The distal end capis a flexible member that closes an opening of the outer sheath bodyon the distal side. Instead of the distal end cap, a member where a guide wire lumen is formed may be fixed to the distal portion of the outer sheath body. In this case, the ultrasound cathetercan be of a rapid exchange type having the guide wire lumen at the distal portion.

30 20 30 31 32 30 21 21 30 21 60 70 The inner sheathis a cylindrical body where a part of the distal side is inserted into the outer sheath. The inner sheathcan include an inner sheath bodyand an inner sheath reinforcing body. A distal portion of the inner sheathis accommodated in the outer sheath bodyso as to be movable along the axis of the outer sheath body. A proximal portion of the inner sheathextends from the outer sheath bodyand the first housingto the proximal side, and is fixed to the second housing.

31 50 31 40 40 32 31 32 32 60 30 20 20 30 60 32 32 31 The inner sheath bodyrotatably accommodates the drive shaft. A distal portion of the inner sheath bodyis positioned relatively close to the transducer uniton a proximal side of the transducer unit. The inner sheath reinforcing bodycan be a circular tube that reinforces an outer peripheral surface of a proximal portion of the inner sheath body. The inner sheath reinforcing bodyis provided in a predetermined range in which the inner sheath reinforcing bodyis more likely to be exposed to the proximal side than the first housing. Therefore, the inner sheathcan stably reciprocate along the axis of the outer sheathwith respect to the outer sheath. Therefore, the inner sheathcan be satisfactorily pushed into the first housing. The inner sheath reinforcing bodymay not be the circular tube. The inner sheath reinforcing bodymay be, for example, a braided wire embedded in the inner sheath body.

40 21 50 50 50 40 21 50 21 50 50 30 50 30 50 50 When the large transducer unithaving a long ultrasound penetration depth is applied such that an image can be acquired in a relatively large space such as an inside of the heart or an inside of a blood vessel of a lower limb or an abdomen, an inner diameter of the outer sheath bodyincreases accordingly. Accordingly, increasing an outer diameter of the drive shaftis not desirable because a load on a proximal portion of the drive shaft, a required rotational driving force, and a heat generation amount increase. However, when the outer diameter of the drive shaftis excessively smaller than that of the transducer unit, a large space is generated between an inner peripheral surface of the outer sheath bodyand an outer peripheral surface of the drive shaft. This large space between the inner peripheral surface of the outer sheath bodyand the outer peripheral surface of the drive shaftcan cause unstable movement of the drive shaftin the rotational direction and the axial direction. The inner sheathis disposed in this large space, and stabilizes the movement of the drive shaftin the rotational direction and the axial direction. The inner sheathdoes not rotate together with the drive shaft. Therefore, the rotational driving force required for the drive shaftand the heat generation amount do not increase.

40 40 41 42 41 50 40 50 51 40 30 40 30 40 28 21 21 24 26 40 28 23 27 40 28 The transducer unittransmits and receives ultrasound to and from a lumen tissue. The transducer unitcan include a transducerthat transmits and receives the ultrasound, and a transducer holding portionwhere the transduceris disposed and which is fixed to the drive shaft. A maximum outer diameter of the transducer unitin a cross section orthogonal to the axis of the drive shaftis larger than a maximum outer diameter of a distal side drive shaft. The maximum outer diameter of the transducer unitis about the same as a maximum outer diameter of the inner sheath, but is not limited to the maximum outer diameter of the transducer unitbeing about the same as the maximum outer diameter of the inner sheath. The transducer unitcan move in the accommodation lumenof the outer sheath bodyin the axial direction of the outer sheath bodybeyond the first bent portionand the second bent portion. That is, the transducer unitcan move in the accommodation lumenfrom the proximal side tubular portionto the second tubular portion. Further, the transducer unitcan rotate around the axis in the accommodation lumen.

21 22 31 21 22 31 The materials that constituent the outer sheath body, the distal end cap, and the inner sheath bodyare not particularly limited as long as the materials are flexible and have strength to some extent. For example, polyolefins such as polyethylene and polypropylene, polyamide, polyesters such as polyethylene terephthalate, fluorine-based polymers such as polytetrafluoroethylene (PTFE) and an ethylene-tetrafluoroethylene copolymer (ETFE), polyether ether ketone (PEEK), polyimide, and the like can be suitably used as the materials for the outer sheath body, the distal end cap, and the inner sheath body.

32 The material that constituents the inner sheath reinforcing bodyis not particularly limited, and for example, stainless steel, polyimide, polyether ether ketone, or the like can be suitably used.

50 80 40 50 51 30 52 51 51 42 51 52 52 77 70 53 52 53 52 55 52 3 FIG. The drive shafttransmits a rotational force and a moving force in the axial direction, which are applied from a drive device(see), to the transducer unit. The drive shaftincludes the flexible distal side drive shaftthat passes through the inner sheath, and a connection pipefixed to a proximal portion of the distal side drive shaft. A distal end of the distal side drive shaftis fixed to the transducer holding portion. The distal side drive shaftcan include, for example, a multilayer coil-shaped tubular body such as a three-layer coil whose winding direction is set to right, left, and right directions alternately. The connection pipecan be, for example, a metal-made circular tube. A proximal portion of the connection pipeis fixed to a rotorthat is rotated in the second housing. A signal linepasses through an inside of the connection pipe. The signal linein the connection pipeis adhered by a sealing agentsuch as an adhesive. Therefore, a fluid cannot flow through the inside of the connection pipe.

50 40 50 28 21 21 When the drive shafttransmits power of rotation, the transducer unitis rotated, and an internal structure of a tissue can be observed 360 degrees from the blood vessel or a heart chamber. Further, the drive shaftcan move in the accommodation lumenof the outer sheath bodyalong the axis of the outer sheath body.

53 50 53 77 40 53 40 80 77 The signal lineis disposed so as to pass through an inside of the drive shaft. The signal linetransmits a signal transmitted from the rotorto the transducer unit. Further, the signal linetransmits a signal detected by the transducer unitto the drive devicevia the rotor.

60 20 60 61 20 62 63 64 65 In the first housing, the proximal portion of the outer sheathis adhered in a liquid-tight manner. The first housingincludes a first hollow portionthat communicates with an inner lumen of the outer sheath, a first port, a first housing proximal portion, a first sealing portion, and an engagement portion.

61 62 28 20 30 50 20 61 63 61 61 64 63 30 50 64 64 63 64 30 30 64 30 62 The first hollow portioncommunicates with the first portand the accommodation lumenof the outer sheath. The inner sheathand the drive shaft, which extend from the outer sheathtoward the proximal side, pass through the first hollow portion. The first housing proximal portionincludes a through hole that communicates with the first hollow portion, and is positioned on the proximal side of the first hollow portion. The first sealing portionis disposed in the through hole of the first housing proximal portion. The inner sheathand the drive shaftpass through the first sealing portion. The first sealing portionis in relatively close contact with the first housing proximal portionin a liquid-tight manner. The first sealing portionis in contact with an outer peripheral surface of the inner sheathso as to be slidable and rotatable along the axis of the inner sheath. The first sealing portionis not particularly limited as long as it is slidable on the outer peripheral surface of the inner sheath, and can be, for example, an O-ring or a cross-cut valve body. The cross-cut valve body is a valve body in which a cut in one surface of a flexible material and a cut in the other surface are made to intersect with each other, and two cuts are made to communicate with each other at a central portion. The first portis an opening portion to which a tube or the like for injecting or discharging a fluid such as a saline solution can be coupled.

65 80 65 65 60 The engagement portionis a portion rotatably supported by a holding portion of the drive devicedescribed later. The engagement portionhas a cylindrical shape and includes a smooth outer peripheral surface. The engagement portioncan be formed, for example, in a groove shape in an outer peripheral surface of the first housing.

70 60 70 30 60 70 60 30 The second housingis disposed on a proximal side of the first housing. In the second housing, the proximal portion of the inner sheathextends from the first housingtoward the proximal side and is adhered in a liquid-tight manner. The second housingcan move close to and away from the first housingalong the axis of the inner sheath.

70 71 30 72 73 74 70 75 76 77 The second housingincludes a second hollow portionthat communicates with an inner lumen of the inner sheath, a second port, a second housing proximal portion, and a second sealing portion. The second housingfurther includes a joint, a connector, and the rotor.

71 72 30 50 30 71 73 71 71 74 73 52 50 74 74 52 52 74 73 50 74 50 72 The second hollow portionallows the second portand the inner lumen of the inner sheathto communicate with each other. The drive shaftextends from the inner sheathtoward the proximal side and passes through the second hollow portion. The second housing proximal portionincludes a through hole that communicates with the second hollow portion, and is positioned on a proximal side of the second hollow portion. The second sealing portionis disposed in the through hole of the second housing proximal portion. The connection pipeof the drive shaftpasses through the second sealing portion. The second sealing portionis in contact with an outer peripheral surface of the connection pipeso as to be slidable in a rotation direction of the connection pipe. The second sealing portionslidably seals a space between the second housing proximal portionand the drive shaft. The second sealing portionis not particularly limited as long as it is slidable on the outer peripheral surface of the drive shaft, and can be, for example, an O-ring. The second portis an opening portion to which a tube or the like for injecting or discharging a fluid such as a saline solution (saline) can be coupled.

75 73 75 751 76 77 75 76 811 80 751 76 811 53 52 76 76 40 53 3 FIG. The jointis fixed to a proximal side of the second housing proximal portion. The jointincludes a joint opening portionon the proximal side, and the connectorand the rotorare disposed in the joint. The connectorcan be coupled to a drive-side connectorof the drive device(see) inserted through the joint opening portion. The connectorcan be mechanically and electrically coupled to the drive-side connector. The signal linethat passes through an inside of the connection pipeis connected to the connector. Therefore, the connectoris connected to the transducer unitvia the signal line.

52 77 77 76 75 77 50 77 77 75 73 77 77 70 70 40 76 53 40 80 53 76 80 The connection pipeis adhered to the rotor. The rotoris rotated integrally with the connectorin the joint. When the rotoris rotated, the drive shaftfixed to the rotoris rotated. Further, the rotoris sandwiched between the jointand the second housing proximal portion, and movement of the rotorin the axial direction can be limited. The rotorcan be rotated in the second housing, and can move along the axis together with the second housing. The transducer unitoutputs ultrasound in response to a signal received via the connectorand the signal line. Further, the transducer unitreceives a reflected wave, converts the reflected wave into a signal, and transmits the signal to the drive devicevia the signal lineand the connector. The drive deviceperforms an appropriate processing on the received signal and displays the processed signal as an image.

60 70 60 70 The material that constituent the first housingand the second housingis not particularly limited as long as it has a strength to some extent. For example, polycarbonate, polyamide, polysulfone, polyarylate, a methacrylate-butylene-styrene copolymer, or the like can be suitably used as the material for the first housingand the second housing.

3 4 4 FIGS.,A, andB 10 80 80 85 81 50 82 81 83 65 10 80 89 81 82 40 88 89 As shown in, the ultrasound catheterdescribed above is connected to and driven by the drive device. The drive devicecan include, on a base, a drive unitthat incorporates a drive source such as a motor and rotationally drives the drive shaft, a movement portionthat moves the drive unitin an axial direction, and a distal side support portionthat rotatably supports the engagement portionof the ultrasound catheter. The drive deviceis connected to a control unitthat controls the drive unitand the movement portion. An image obtained by the transducer unitis displayed on a display unitconnected to the control unit.

82 81 82 82 81 86 85 The movement portioncan firmly hold the drive unit. The movement portioncan be, for example, a feed mechanism driven by a drive source such as a motor. The movement portionmoves the fixed drive unitforward and backward along a groove railon the base.

81 811 76 10 812 75 10 76 811 81 40 50 The drive unitincludes a drive connectorthat can be connected to the connectorof the ultrasound catheter, and a proximal side support portionthat can be connected to the jointof the ultrasound catheter. When the connectoris connected to the drive connector, the drive unitcan transmit and receive a signal to and from the transducer unit, and can rotate the drive shaft.

83 93 85 94 93 95 94 94 96 65 10 97 96 98 96 98 95 99 65 10 99 65 65 94 94 95 65 10 The distal side support portioncan include a support basethat protrudes from the base, an outer ringfixed to the support base, and an inner ringslidably disposed inside the outer ring. The outer ringcan include two semi-circular arc-shaped outer ring membersthat are divided so as to receive the engagement portionof the ultrasound catheterfrom an outside, a hinge portionthat couples the two outer ring membersin an openable and closable manner, and a fixing mechanismthat can fix the two outer ring membersin a closed state and can release the fixing. The fixing mechanismcan include, for example, a hook and a portion with which the hook is detachably engaged, but the structure is not limited to a hook and a portion with which the hook is detachably engaged. The inner ringcan include two semi-circular arc-shaped inner ring membersthat are divided so as to receive the engagement portionof the ultrasound catheterfrom an outside. The inner ring memberssurround and are in relatively close contact with the engagement portion, and can be rotated together with the engagement portionin the outer ring. That is, the outer ringand the inner ringconstitute a bearing. The structure of the distal side support portion is not particularly limited as long as the engagement portionof the ultrasound cathetercan be rotatably supported.

10 81 50 40 50 41 52 50 41 20 Ultrasound scanning of the ultrasound catheteris performed by transmitting a rotational motion of the drive unitto the drive shaftand rotating the transducer unitfixed to a distal end of the drive shaft. Accordingly, ultrasound transmitted and received by the transducercan be used to scan in a substantially radial direction. Further, the movement portioncan pull the drive shafttoward the proximal side. Accordingly, the transducercan be moved toward the proximal side while being rotated. Therefore, a 360° cross-sectional image of a surrounding tissue of the blood vessel or the heart chamber can be obtained in a scanning manner along the axis of the outer sheathto any position.

10 90 90 90 91 92 91 72 92 62 90 90 62 The ultrasound catheteris connected to a pump device. The pump devicecan circulate a fluid. The pump devicecan include a supply pipethat supplies the fluid and a recovery pipethat recovers the fluid. The supply pipeis connected to the second port. The recovery pipeis connected to the first port. A pump mechanism of the pump deviceis not particularly limited, and can be, for example, a peristaltic pump, a centrifugal pump, a diaphragm pump, or the like. The pump devicemay be of a non-circulation type. In this case, the first portis connected to a tube connected to a waste container.

10 80 88 89 90 1 The ultrasound catheter, the drive device, the display unit, the control unit, and the pump deviceconstitute one ultrasound catheter system.

10 10 7 FIG. Next, a method for observing a biotissue from a lumen in a living body by using the ultrasound catheteraccording to the present embodiment will be described. Here, as shown in, a treatment in which the ultrasound catheteris inserted into a right atrium HRa from a femoral vein and an atrial septum HA is punctured will be described as an example.

10 91 90 72 92 62 3 FIG. First, before the ultrasound catheteris inserted into the blood vessel, as shown in, the supply pipeof the pump deviceis connected to the second port, and the recovery pipeis connected to the first port.

2 3 FIGS.and 70 60 40 21 30 50 50 Next, as shown in, the second housingis brought closest to the first housing. At this time, the transducer unitis positioned in the vicinity of a distal end of the outer sheath body. Since the inner sheathcovers the drive shaftover substantially an entire length, the drive shaftstably rotates during driving, and it is possible to receive a signal and acquire an image with relatively high accuracy.

90 71 72 70 50 30 50 70 70 50 74 70 50 30 30 50 30 20 40 21 21 2 2 FIGS.A andB Next, the pump deviceis driven to inject, for example, the saline solution into the second hollow portionfrom the second portof the second housing. Accordingly, the saline solution flows into a gap between the drive shaftand the inner sheath, as indicated by an alternate long and short dash line in. The drive shaftrotatably passes through the second housing. However, a space between the second housingand the drive shaftis sealed by the second sealing portion. Therefore, the saline solution does not leak to an outside from the space between the second housingand the drive shaft. Therefore, the saline solution can be effectively introduced into the inner sheath. The saline solution injected into the gap between the inner sheathand the drive shaftmoves toward the distal side and reaches the distal side with respect to the inner sheath. Accordingly, a space between the outer sheathand the transducer unitis filled with the saline solution. The distal portion of the outer sheath bodyis closed without forming an opening. Therefore, the saline solution is not discharged from the distal portion of the outer sheath body.

20 30 30 61 60 30 60 60 30 64 60 30 62 10 40 Next, the saline solution flows into a gap between the outer sheathand the inner sheathfrom a distal side of the inner sheath, and the saline solution moves to the proximal side in the gap. Thereafter, the saline solution flows into the first hollow portionof the first housing. The inner sheathpasses through the first housingso as to be movable along the axis. However, a space between the first housingand the inner sheathis sealed by the first sealing portion. Therefore, the saline solution does not leak to an outside from the space between the first housingand the inner sheath. Therefore, the saline solution can be effectively discharged from the first port. Accordingly, air in the ultrasound cathetercan be removed, and a periphery of the transducer unitcan be filled with the saline solution.

90 10 Next, circulation of the saline solution is continued or stopped by the pump device, and the ultrasound cathetercan be inserted into the lumen in the living body.

10 10 10 10 100 100 7 FIG. Next, a surgeon percutaneously inserts the ultrasound catheterinto the femoral vein. Then, as shown in, under observation with X-rays, the surgeon pushes forward the ultrasound catheterinserted into the blood vessel, and causes the ultrasound catheterto reach the right atrium HRa via an inferior vena cava Iv. The surgeon disposes a most distal end of the ultrasound catheterat a position beyond an oval fossa Fo that is an observation target (on a side close to a superior vena cava with respect to the oval fossa Fo). Further, the surgeon percutaneously inserts a sheathinto the femoral vein, and causes the sheathto reach the right atrium HRa via the inferior vena cava Iv.

3 5 FIGS.and 10 80 65 60 99 65 99 96 96 98 60 83 Thereafter, as shown in, the ultrasound catheteris coupled to the drive device. That is, the engagement portionof the first housingis surrounded by the two inner ring members, and the engagement portionand the inner ring membersare disposed between the two outer ring membersin an open state. Thereafter, the two outer ring membersare closed, and fixed by the fixing mechanism. Accordingly, the first housingis supported by the distal side support portionso as to be rotatable and immovable in the axial direction.

75 10 812 81 40 80 50 81 82 Next, the jointof the ultrasound catheteris connected to the proximal side support portionof the drive unit. Accordingly, a signal can be transmitted and received between the transducer unitand the drive device. Further, the drive shaftcan rotate and move by the drive unitand the movement portion.

6 6 FIGS.A andB 3 FIG. 50 40 80 82 10 89 89 88 88 41 88 Next, as shown in, the surgeon performs a pull-back operation while rotating the drive shaftwhile acquiring image data from the transducer unitby the drive device. The pull-back operation can be performed by operating the movement portionconnected to the proximal portion of the ultrasound catheterby the control unit. The acquired data is subjected to a digital processing by the control unit, and then displayed on the display unitas image data (see). The display unitcan display the image data substantially in real time. The surgeon disposes the transducerat a specific position in a rotation direction and an axial direction in which the oval fossa Fo can be observed while checking the display unit.

60 83 20 50 80 20 24 20 20 24 20 41 50 28 41 28 20 20 41 Next, the surgeon rotates the first housingrotatably supported by the distal side support portionto rotate the outer sheathin a state where pull-back and rotation of the drive shaftby the drive deviceare fixed. The outer sheathincludes the first bent portionat the distal portion of the outer sheath. Therefore, the surgeon can freely adjust a distance and an angle of an offset portion of the outer sheathon the distal side of the first bent portionwith respect to the observation target. When an offset lower portion of the outer sheathis rotated, positions of the transducerand the drive shaftdisposed in the accommodation lumenalso change accordingly. Therefore, the surgeon can freely adjust the distance and the angle of the transducerdisposed in the accommodation lumenof the outer sheathwith respect to the observation target. For example, by rotating the outer sheath, the surgeon can bring the transducerrelatively close to the oval fossa Fo that is an observation target such that the oval fossa Fo can be rather easily observed.

101 100 101 10 101 101 101 100 10 Next, the surgeon causes a septum puncture needleto reach the right atrium HRa via the sheath. Next, the surgeon checks that the septum puncture needleis directed toward the oval fossa Fo under ultrasound observation by the ultrasound catheter. Thereafter, the surgeon punctures the oval fossa Fo with the septum puncture needleunder the ultrasound observation. Accordingly, it is possible to reliably prevent a portion other than the oval fossa Fo from being punctured by the septum puncture needle. Thereafter, the surgeon removes the septum puncture needle, the sheath, and the ultrasound catheter, and completes the procedure.

10 20 28 30 28 20 50 30 20 41 30 28 50 20 24 28 25 27 24 25 27 24 28 20 30 As described above, the ultrasound catheteraccording to the present embodiment includes: the outer sheathin which the accommodation lumenthat extends from the proximal end to the distal end is formed; the inner sheaththat can move in the accommodation lumenalong the axis of the outer sheath; the drive shaftthat can rotate in the inner sheathand/or the outer sheath; and the transducerthat is disposed on the distal side of the inner sheathin the accommodation lumen, and that is fixed to the distal end of the drive shaft, in which the outer sheathincludes the first bent portionthat is bent and shaped in advance at a predetermined angle on the proximal side of a most distal end of the accommodation lumen, and the first tubular portionand the second tubular portionthat have the axis having the radius of curvature larger than the radius of curvature of the axis of the first bent portion, the first tubular portionand the second tubular portionbeing positioned on the distal side of the first bent portionand on the proximal side of the most distal end of the accommodation lumen, in which the outer sheathis rotatable with respect to the inner sheath.

20 30 10 41 28 25 27 24 10 10 Since the outer sheathis rotated with respect to the inner sheath, the ultrasound catheterconfigured as described above can freely adjust the distance and the angle of the transducer, which is in the accommodation lumenpositioned in the first tubular portionand the second tubular portionon the distal side of the first bent portion, with respect to the observation target. Therefore, the ultrasound cathetercan acquire an image of the observation target with relatively high accuracy even when the ultrasound catheteris inserted into a large inner lumen.

25 27 41 28 The axes of the first tubular portionand the second tubular portionare linear. Accordingly, since the transducerto be moved in the accommodation lumenis moved linearly, obtained images can be rather easily connected in the axial direction, and a relatively highly accurate three-dimensional image can be acquired.

20 24 26 20 41 The outer sheathcan include the first bent portionand the second bent portionat different positions in the axial direction. Accordingly, as compared with a case where the outer sheathincludes only one bent portion, it is relatively easy to dispose the transducerat a desirable position.

27 25 20 20 20 20 41 20 The second tubular portion, which is at least one of the bent portions, is bent toward a side opposite to the first tubular portion, which is at least one of other bent portions. Accordingly, the distal portion of the outer sheathcan be disposed at a position offset from the proximal portion of the outer sheathwhile having a shape close to parallel to the proximal portion of the outer sheath. Therefore, the distal portion of the outer sheathis rather easily disposed along a wall of the inner lumen of the heart or the inner lumen such as a blood vessel. Therefore, the transducerthat pulls back along the axis can be disposed at a desirable position with respect to the observation target in a large range of the outer sheathin the axial direction.

41 28 24 26 41 24 26 28 The transducercan move in the accommodation lumenin the axial direction beyond the first bent portionand the second bent portion. Accordingly, the transducercan acquire an image of an internal structure of a living body positioned in a large range beyond the first bent portionand the second bent portionin an axial direction of the accommodation lumen.

24 26 2 20 50 The bending angle of the axis of the first bent portionand the second bent portioncan be, for example, 5° to 20°. When the bending angle is not too small, it is relatively easy to set the offset amount Lof the outer sheathto a desirable value. Further, when the bending angle is not too large, rotation and movement in the axial direction of the drive shaft, which moves in the axial direction while being rotated in a state of being bent in the bent portion, are less likely to be hindered.

20 23 24 1 24 20 23 23 1 2 20 The outer sheathincludes the proximal side tubular portionon the proximal side of the first bent portionthat is a bent portion on a most proximal side. The distal portion length L, which is a length from the first bent portionto the most distal end of the outer sheathalong the linear reference line X where the axis of at least the distal portion of the proximal side tubular portionis positioned, is 20 mm to 150 mm. Accordingly, a length of a portion offset with respect to the proximal side tubular portioncan be set to a length appropriate for observation in a heart or a blood vessel having a large inner lumen. Further, since the distal portion length Lis an appropriate length, it is rather easy to set the offset amount Lof the outer sheathto a length appropriate for observation in the heart or the blood vessel having the large inner lumen.

20 23 24 2 23 24 20 2 20 The outer sheathincludes the proximal side tubular portionon the proximal side of the first bent portionthat is a bent portion on the most proximal side. The offset amount Lthat is a length from the linear reference line X where the axis of at least the distal portion of the proximal side tubular portionis positioned to the axis of the portion farthest in the direction perpendicular to the reference line X of a portion on the distal side of the first bent portionof the outer sheathis 5 mm to 30 mm. Since the offset amount Lhas an appropriate magnitude, it is rather easy to bring the outer sheathclose to the observation target in the heart or the blood vessel having the large inner lumen.

1 10 80 10 10 20 28 30 28 20 50 30 20 41 30 28 50 60 20 50 30 70 60 30 50 20 24 28 25 27 24 25 27 24 28 20 30 80 812 70 82 812 81 50 83 60 The ultrasound catheter systemaccording to the present embodiment includes the ultrasound catheterand the drive devicethat drives the ultrasound catheter, in which the ultrasound catheterincludes the outer sheathin which the accommodation lumenthat extends from the proximal end to the distal end is formed; the inner sheaththat can move in the accommodation lumenalong the axis of the outer sheath; the drive shaftthat can rotate in the inner sheathand/or the outer sheath; the transducerdisposed on the distal side of the inner sheathin the accommodation lumen, and fixed to the distal end of the drive shaft; the first housingto which the proximal portion of the outer sheathis fixed and through which the drive shaftand the inner sheathpass; and the second housingthat is disposed on the proximal side of the first housing, to which the proximal portion of the inner sheathis fixed, and that rotatably holds the drive shaft, in which the outer sheathincludes the first bent portionthat is bent and shaped in advance at a predetermined angle on the proximal side of the most distal end of the accommodation lumen, and the first tubular portionand the second tubular portionthat have the axis having the radius of curvature larger than the radius of curvature of the axis of the first bent portion, the first tubular portionand the second tubular portionbeing positioned on the distal side of the first bent portionand on the proximal side of the most distal end of the accommodation lumen, in which the outer sheathis rotatable with respect to the inner sheath, in which the drive deviceincludes the proximal side support portionthat can support the second housing, the movement portionthat can move the proximal side support portionin the axial direction, the drive unitthat can transmit the rotational force to the drive shaft, and the distal side support portionthat can rotatably support the first housing.

60 83 20 60 30 1 41 28 25 27 24 1 1 Since the first housingsupported by the distal side support portionis rotatable, by rotating the outer sheathfixed to the first housingwith respect to the inner sheath, the ultrasound catheter systemconfigured as described above can freely adjust the distance and the angle of the transducer, which is in the accommodation lumenpositioned in the first tubular portionand the second tubular portionon the distal side of the first bent portion, with respect to the observation target. Therefore, the ultrasound catheter systemcan acquire an image of the observation target with high accuracy even when the ultrasound catheter systemis inserted into, for example, a large inner lumen.

10 41 20 28 28 10 41 41 28 20 20 41 Further, the present disclosure also provides a treatment method. The present treatment method includes: inserting, into the blood vessel, the ultrasound catheterin which the transducerrotatable and movable in the axial direction is provided in the outer sheathin which the accommodation lumenthat extends from the proximal end to the distal end is formed and that includes the bent portion bent and shaped in advance at a predetermined angle on the proximal side of the most distal end of the accommodation lumen, and causing the ultrasound catheterto reach the right atrium HRa via the inferior vena cava Iv; acquiring an ultrasound image by moving the transduceralong the axis while rotating the transducerin the accommodation lumen; rotating the outer sheathto adjust a position of a portion on the distal side of the bent portion of the outer sheathwith respect to the oval fossa Fo that is an observation target; and acquiring an ultrasound image of the oval fossa Fo by the transducer.

20 10 41 20 20 In the treatment method configured as described above, by rotating the outer sheathof the ultrasound catheterinserted into the large inner lumen of the heart, the position and the angle of the transducer, which is disposed in the outer sheathon the distal side of the bent portion of the outer sheath, with respect to the oval fossa Fo can be freely adjusted. Therefore, in the present treatment method, it is possible to acquire an image of the oval fossa Fo, which is the observation target, with relatively high accuracy even when the treatment is performed in the large inner lumen of the heart. Therefore, in the present treatment method, for example, it is possible to safely puncture the oval fossa Fo while checking the oval fossa Fo.

8 FIG. 10 10 10 The present disclosure is not limited to the embodiment described above, and various modifications can be made by those skilled in the art within a scope of the technical idea of the present disclosure. For example, as shown in, the ultrasound catheteraccording to the present embodiment may be inserted into one of two adjacent blood vessels and used to observe a blood vessel into which the ultrasound catheteris not inserted. For example, the ultrasound cathetercan be inserted into a vein Ve of a lower limb or an abdomen to observe an inside of an artery Ar adjacent to the vein Ve. Therefore, for example, when a procedure of inserting an atherectomy device into an artery and scraping and removing a calcified lesion is performed, the calcified lesion and the atherectomy device in the artery Ar can be observed.

9 FIG.A 24 As in a first modification shown in, only one bent portion (for example, the first bent portion) may be provided.

9 FIG.B 10 24 26 20 24 26 50 24 26 20 As in a second modification shown in, the ultrasound cathetermay include at least two bent portions (for example, the first bent portionand the second bent portion) bent toward the same side. Accordingly, in the outer sheath, respective angles of the first bent portionand the second bent portioncan be reduced. Therefore, it is possible to reduce a load on the drive shaftthat is movable in an axial direction while being rotated in the first bent portionand the second bent portion, and to help prevent occurrence of a rotation failure or a failure in movement in the axial direction. Further, since the outer sheathcan be largely bent as a whole by at least two bent portions, orientation is facilitated.

9 FIG.C 10 29 20 29 20 29 29 10 10 As in a third modification shown in, in the ultrasound catheter, a wirethat protrudes from a distal end of the outer sheathin a distal end direction may be formed. An outer diameter of the wireis smaller than an outer diameter of the outer sheath. A distal portion of the wireis curved. The wirehas a function as a guide wire for selecting a blood vessel to be advanced when the ultrasound catheteris pushed forward in the blood vessel. Accordingly, the ultrasound catheteris rather easily pushed forward in a blood vessel.

The detailed description above describes embodiments of an ultrasound catheter and an ultrasound catheter system that acquire an image by being inserted into an inner lumen such as a heart or a blood vessel. These disclosed embodiments represent examples of the ultrasound catheter and the ultrasound catheter system that acquire an image by being inserted into an inner lumen such as a heart or a blood vessel disclosed here. The invention is not limited, however, to the precise embodiments and variations described. Various changes, modifications and equivalents can be effected by one skilled in the art without departing from the spirit and scope of the invention as defined in the accompanying claims. It is expressly intended that all such changes, modifications and equivalents which fall within the scope of the claims are embraced by the claims.